Pet owners, particularly cat owners, dislike the unpleasant routine of maintaining a clean environment by containing and disposing of animal waste. Generally, cats are trained to defecate and urinate in a litter box, which is supplied with some type of disposable litter. The litter can be composed of a number of different materials. Some litter formulations include bentonite clay or silica gel to absorb feline urine and allow the cat to bury its feces. These may be objectionable to some individuals who are worried about the potential health effects of bentonite or silica dust on themselves or their pets. Furthermore, some individuals who have allergies to certain types of dust also find it difficult to use these products. Other formulations are made of ground grain, such as wheat, or ground corn cob. Generally, unprocessed grains provide limited absorption of aqueous material such as urine and must therefore be supplemented with an additional material for absorption of the urine in order to provide adequate performance. U.S. Pat. No. 4,727,824 describes a cellulosic hull material (cereal grain hulls, peanut hulls, soybean, rapeseed, sunflower, or cottonseed hulls) in combination with a nitrogenous compound absorber (cyclodextrin). U.S. Pat. No. 4,883,021 describes a litter formulation comprising plant pulp, cereal grain hull, and a polyacrylate polymer (polyglycerol acrylate or polypropyl acrylate) to absorb nitrogenous waste.
Many litters have been formulated to provide a clump when contacted with urine. The clump can be removed, thereby removing the urine from the litter box. These litters have been developed to address the common problem of very unpleasant odor in the litter box due to urine accumulation. In addition to the aesthetic effect for the human owner, presence of urine odor in the litter box also creates an effect on the cat, often causing it to avoid the box and urinate in undesirable places. Some cats have even been known to avoid urinating because the box is so offensive, resulting in a detrimental health effect on the cat.
Clumping litters utilize a number of different materials, including bentonite clay, corn cob, corn, and wheat. U.S. Pat. No. 5,152,250, for example, describes a clumping litter comprising a biodegradable carrier such as granulated peanut shells, having grain flour and mineral oil intermixed therewith to provide a clumping effect. U.S. Pat. No. 5,176,107 describes a clumping litter comprising particular material having a liquid-responsive, adhesive material mixed with a sorbent material in particulate form. U.S. Pat. No. 4,206,718 describes a litter composition formed of alfalfa combined with a gelatinizable carbohydrate, such as flour. While these litters do provide a means for removal of clumps of litter containing appreciable amounts of urine, they also require regular maintenance consisting of sifting through the litter material and scooping out the clumps. Many pet owners find this duty unpleasant enough to avoid it, choosing instead to dispose of the entire contents of the litter box at regular intervals. This can actually increase costs, since accumulation of clumps makes it difficult for the cat to dig in the box and necessitates more frequent changes of litter.
With most non-clumping litters, urine accumulates in the litter and necessitates frequent disposal due to excessive unpleasant odor. Therefore, the pet owner must generally choose between regular scooping or regular disposal. Both require significant maintenance time and are unpleasant.
What is needed is an absorbent composition that provides a low-maintenance pet litter to manage urine absorption and odor and decrease the frequency of litter disposal.